/* roulang page: index */
:root {
      --primary: #E94057;
      --primary-hover: #c92d44;
      --secondary-dark: #1A1A2E;
      --secondary-blue: #0F3460;
      --accent: #00D2FF;
      --bg-light: #F8F9FC;
      --text-main: #1A1A2E;
      --text-muted: #6B7280;
      --border-light: #E5E7EB;
      --shadow-card: 0 4px 20px rgba(26,26,46,0.08);
      --shadow-hover: 0 12px 32px rgba(233,64,87,0.15);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --nav-width: 240px;
      --transition: 0.25s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: 'Noto Sans SC', 'Inter', system-ui, sans-serif;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.75;
      display: flex;
      min-height: 100vh;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      font-family: 'Inter', 'Noto Sans SC', system-ui, sans-serif;
    }
    .data-font {
      font-family: 'Rajdhani', 'Inter', sans-serif;
    }
    /* 左侧导航桌面样式 */
    .app-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: var(--nav-width);
      height: 100vh;
      background-color: var(--secondary-dark);
      display: flex;
      flex-direction: column;
      padding: 2rem 1.25rem;
      z-index: 50;
      box-shadow: 2px 0 15px rgba(0,0,0,0.2);
      transition: transform var(--transition);
    }
    .nav-logo {
      text-align: center;
      margin-bottom: 2.5rem;
    }
    .nav-logo img {
      height: 40px;
      width: auto;
      filter: brightness(0) invert(1);
    }
    .nav-links {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }
    .nav-link {
      display: flex;
      align-items: center;
      gap: 0.75rem;
      color: rgba(255,255,255,0.65);
      text-decoration: none;
      padding: 0.75rem 1rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      transition: all var(--transition);
      border-left: 3px solid transparent;
      font-size: 1rem;
    }
    .nav-link i {
      width: 20px;
      font-size: 1.1rem;
      text-align: center;
    }
    .nav-link:hover {
      color: #ffffff;
      background-color: rgba(255,255,255,0.05);
      border-left-color: var(--primary);
    }
    .nav-link.active {
      color: #ffffff;
      background-color: rgba(233,64,87,0.15);
      border-left-color: var(--primary);
    }
    .nav-social {
      display: flex;
      justify-content: center;
      gap: 1rem;
      margin-top: 2rem;
    }
    .nav-social a {
      color: rgba(255,255,255,0.6);
      font-size: 1.2rem;
      transition: color var(--transition);
    }
    .nav-social a:hover {
      color: var(--primary);
    }
    /* 主内容区域 */
    .main-content {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      min-height: 100vh;
    }
    /* 移动端导航按钮 */
    .mobile-nav-toggle {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 1.5rem;
      cursor: pointer;
    }
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background-color: var(--secondary-dark);
      z-index: 40;
      align-items: center;
      justify-content: space-between;
      padding: 0 1.25rem;
      box-shadow: 0 2px 10px rgba(0,0,0,0.3);
    }
    /* 组件样式 */
    .container-custom {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 2rem;
    }
    .btn-primary {
      background: linear-gradient(90deg, var(--primary), #f05a28);
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: 12px;
      border: none;
      cursor: pointer;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      text-decoration: none;
      box-shadow: 0 4px 15px rgba(233,64,87,0.25);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 25px rgba(233,64,87,0.4);
      filter: brightness(1.1);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 30px;
      border-radius: 12px;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      text-decoration: none;
    }
    .btn-outline:hover {
      background-color: rgba(233,64,87,0.08);
      transform: translateY(-2px);
    }
    .badge-data {
      background-color: var(--secondary-blue);
      color: var(--accent);
      font-family: 'Rajdhani', sans-serif;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 8px;
      font-size: 1.1rem;
      display: inline-flex;
      align-items: center;
      gap: 0.25rem;
    }
    .card {
      background: white;
      border-radius: var(--radius-lg);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .section-spacing {
      padding: 80px 0;
    }
    .faq-item {
      background: white;
      border-radius: var(--radius-md);
      padding: 18px 24px;
      margin-bottom: 12px;
      border-left: 4px solid var(--primary);
      cursor: pointer;
      transition: all var(--transition);
    }
    .faq-item:hover {
      box-shadow: var(--shadow-hover);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    footer {
      background-color: var(--secondary-dark);
      color: rgba(255,255,255,0.7);
      padding: 60px 0 30px;
    }
    @media (max-width: 1023px) {
      .app-nav {
        transform: translateX(-100%);
      }
      .app-nav.open {
        transform: translateX(0);
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
      }
      .mobile-nav-toggle {
        display: block;
      }
      .section-spacing {
        padding: 60px 0;
      }
      .container-custom {
        padding: 0 1.5rem;
      }
    }
    @media (max-width: 767px) {
      .card {
        padding: 20px;
      }
      h1 {
        font-size: 2rem !important;
      }
      h2 {
        font-size: 1.75rem !important;
      }
      .btn-primary, .btn-outline {
        width: 100%;
        justify-content: center;
      }
    }